In the aftermath of a prison takeover that left a corrections officer dead, state officials announced a sweeping investigation that, as of Thursday morning, considered all 120 inmates inside James T. Vaughn Correctional Center’s Building C to be suspects.

Authorities regained control of the facility shortly after 5 a.m. Thursday, ending an 18-hour standoff in which four Department of Correction employees were taken hostage by prisoners. Two of the hostages had been released earlier on Wednesday, and tactical teams were able to rescue a female counselor when they breached the barricaded building. A fourth victim, 47-year-old Sgt. Steven Floyd Sr. was found unresponsive and pronounced dead around 5:30 a.m.